Switching Undo Tablespace

Oracle Database can have more than one Undo tablespace, but only one undo tablespace will be online per instance. To switch the undo tablespace,

SQL> Alter system set Undo_Tablespace = 'undotbs2' scope=both;

Note: The active transactions will continue to use the old undo tablespace. The status of the old undo tablespace will be PENDING OFFLINE. The undo tablespace cannot be dropped when its status is pending offline. When all the active transactions are completed then the staus will be changed to offline. The new transactions will use the new undo tablespace.

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